Since the opamp forces V(inv) to be 0V, the current in the 10K resistor is 1mA (10V/10K). The charge accumulated by the capacitor Q=C(ΔV) = it.
Rearrange, ΔV = it/C = (1e-3)t/1000e-6 = (1e-3)t/1e-3) = t, or 1V/1s. However, the current flow causes the output of the opamp to go negative...